In the cannabis plant family, hemp is the good seed. Marijuana, the evil weed. Michael Bowman, a gregarious Colorado farmer who grows corn and wheat, has been working his contacts in Congress in an attempt to persuade lawmakers that hemp has been framed, unfairly lumped with the stuff people smoke to get high.

Somehow over time, as Bowman’s pitch goes, hemp, which is used to make paper, oils and a variety of useful products was mistaken for its twin, marijuana — aka pot, chronic, blunt and weed — a medicinal drug loaded with tetrahydrocannabinol that buzzes the mind. Hemp got caught up in the legendary crusade against pot popularized by the movie “Reefer Madness.” All varieties of cannabis ended up on the most-wanted list, outlawed by Congress as well as lawmakers in other nations, inspiring people to kill it on sight.

Bowman’s message is simple: Be sensible. “Can we just stop being stupid? Can we just talk about how things need to change?”

While the United States ranks as the world’s leading consumer of hemp products — with total sales exceeding $43 million in 2011 — it is the only major industrialized country that bans growing it, even though 11 states have passed measures removing barriers to hemp production and research. Ninety percent of the U.S. supply comes from Canada.

Since Colorado and Washington legalized marijuana by ballot initiatives last fall, a group of farmers and activists have been pushing to revive a crop they say offers a solution to vexing environmental, health and economic challenges.

Proponents value hemp both for how it grows — quickly and in a wide geographic range, without requiring much in terms of water, pesticides and fertilizers — and what it can produce. Its seeds and oil are fodder for health and beauty products, while the strength of its natural fiber makes it a good candidate to be used as a building composite. Combine hemp with water and lime and you get “hempcrete,” which can help construct a house; process it differently and it can make up a BMW’s interior door panel.

But Bowman’s project to plant nearly 40 hectares of hemp on his 1,170-hectare farm on April 30 — to coincide with the 80th birthday of his friend singer Willie Nelson, known for his support for hemp and marijuana legalization — could run afoul of the Agriculture Department’s farm program, which helps subsidize his corn and wheat. He also grows edible beans, alfalfa and, occasionally, sunflowers.

In a statement, Agriculture Department spokesman Justin DeJong said that since hemp is considered “a Schedule I controlled substance” under the Controlled Substances Act of 1970, it “cannot be grown on farmland” receiving federal commodity subsidies. If convicted of a violation, a farmer cannot get subsidies for five years.

Drug Enforcement Administration spokesman Rusty Payne said in a statement that the controlled-substance law refers “to all cannabis plants, regardless of their THC content,” and that only marijuana growers with a DEA permit can grow it.

It didn’t used to be this way. In the colonial era, Benjamin Franklin published an article touting hemp’s virtues, and Virginia farmers were allowed to pay their taxes in hemp. A USDA botanist grew a half-dozen varieties of hemp on federal property in the 1920s. The U.S. government urged farmers to grow “Hemp for Victory” during World War II to provide the raw material for ropes, sailors’ uniforms and other supplies.

But a couple of factors — the high taxes the federal government imposed on growing hemp in the late 1930s and again in the early ’50s, and then the DEA’s interpretation of the 1970 law — made producing hemp nearly impossible.

But starting in 1999, states began to pass legislation making it easier to either grow industrial hemp or conduct research on it. These measures, however, have had little practical effect. Since the DEA only grants permits in rare instances and demands costly, elaborate security precautions, large-scale hemp growing in the United States is not viable.

The Canadian government, meanwhile, recently announced it would invest nearly $100,000 in marketing hemp and researching which varieties would thrive in different regions of the country.

Canadian Embassy spokesman Chris Plunkett described industrial hemp as “an important crop” for Canada because it grows well in the northern prairie “where other crops, due to climate, cannot grow,” and can be rotated in to break disease cycles.

In the United States, its advocates describe hemp in glowing terms. It can be grown organically with relative ease, and its stalks not only store carbon but could potentially produce biomass energy. The oil is rich in protein and Omega-3 fats and can be eaten as well as be used in products such as Dr. Bronner’s Magic Soaps. Hemp seeds are sold as snacks, and it can be made into paper as well as a building composite to replace fiberglass and in some instances concrete.

Lynda Parker, a Denver-based citizen advocate, first learned about hemp while tracking legislation for a political science class she took in 1996. Five years ago, after retiring, she decided to lobby full time for legalization.

“If we’re serious about climate change and the environment, there is no single thing we can do that is more impactful,” she said.

Parker and Bowman, introduced to each other by a Colorado Department of Agriculture official, pushed several efforts in the Legislature aimed at reintroducing hemp.

They worked hard to distinguish hemp — which can actually make marijuana less potent when the two plants cross-fertilize — from pot, working to overcome what they called “the giggle factor.”

“People would ask, ‘Does this mean I can smoke my drapes?’ It’s always the drapes,” Parker recalled.

Victory came Nov. 6, when Colorado voters approved Amendment 64, which not only legalized pot but required “the general assembly to enact legislation governing the cultivation, processing, and sale of industrial hemp.”

Those working on the federal law describe it as a simple matter of economics. Oregon Democratic Sen. Ron Wyden, who introduced legislation last Congress with Kentucky Republican Sen. Rand Paul to decouple hemp from marijuana as a controlled substance and plans to push for the bill again this year, noticed the seeds sold as a snack under the name “hemp hearts” last summer at his local Costco in Tigard, Oregon.

“Why would you say you can sell it at your local Costco, but farmers around the world get to make most of the money?” Wyden asked.

Even potential Canadian competitors are trying to assist the hemp vanguard in the U.S. As Parker and Bowman worked on their state’s ballot initiative, the Canadian Consulate in Denver served as unofficial advisers. They flew Canadian Mounties and an expert in composites to discuss the logistics of enforcement and processing hemp once it’s legal and funded Parker’s trip to Winnipeg to attend an industry meeting.

“If and when it becomes legal to grow hemp in the United States, that’s just going to add credence and credibility to what we’re doing,” said Hemp Oil Canada President Shaun Crew, who has already registered the name “Hemp Oil USA” for when he opens up shop south of the border.

Still, that day may be a while off.

National Farmers Union President Roger Johnson, whose group supports legalization, failed to help North Dakotan farmers overcome federal opposition to hemp cultivation while serving as the state’s agriculture commissioner.

“I don’t want to throw cold water on this,” Johnson said, with hesitation in his voice. “We were in this fight for 10 years straight and got absolutely nowhere.”

Crew is in favor of the campaign, though he warned his American allies not to exaggerate hemp’s potential and become convinced “there’s a big pot of gold at the end of the hemp rainbow.”

“This isn’t the be-all and end-all,” Crew said, noting that 15 years after legalization, hemp occupies only 19,500 hectares of land in Canada. “We’re just a blip on the radar screen of agriculture in our two countries.”